LIBERALIZAÇÃO COMERCIAL E DEMANDA POR TRABALHO QUALIFICADO NO BRASIL

This paper aims to understand the dynamic of the relative demand for skilled labor in Brazilian industry, during the last decade. Thus, presenting evidences that relative demand for skill increased overall in the period, it seeks to explain this movement, at least in part. For this, we test the hypothesis of skill biased technological changes in an environment of economic opening. The results indicate that a greater share of imported intermediate goods in factories, signaled by the reduction in the tariffs charged on these goods, explains the shift in relative demand for skilled labor, throughout an increasing in the relative productivity between skilled and unskilled workers. This points out to the fact that the hypothesis of skill biased technological changes explains, at least in part, the shift in the relative demand for skilled labor.

Essays on Asset Pricing and Downside Risk

This dissertation contributes to the recent and diverse literature on the relation between downside risk and asset prices. In chapter one, we use a famous quote among professional investors, "focus on the downside, and the upside will take care of itself", to motivate a representative consumer-investor who only cares about the downside. The consumption-based asset pricing model that emerges from this idea explains the main existing puzzles found within the asset pricing literature. These include the equity premium and the risk-free rate puzzles, the countercyclicality of the equity premium and the procyclicality of the risk-free rate. The model is parsimonious, requiring only three preference-related parameters: the time discount factor, the elasticity of intertemporal substitution, and the downside risk aversion. When we use the model to understand the relation between returns and consumption in the US, we find that the fitted parameter values are consistent with what is expected from the micro foundations. In chapter two, we show that the model proposed in chapter one can also explain the financial puzzles in other developed countries. This is an important step in the empirical validation of the model. The estimated parameters are robust across highly capitalized countries and qualitatively close to the ones obtained for the US. Moreover, the risk measure under the quantile utility model can better justify the differences in risk premia across countries when compared to the risk measure under the expected utility model. In chapter three, we evaluate the effect of margin requirements on asset prices, an additional channel for the relation between downside risk and prices. We provide evidences of the existence of an aggregate margin-related premium in the economy. In particular, we show that (i) a margin-related factor is able to predict future excess returns of the S&P 500 and (ii) stocks with high betas on the margin-related factor pay on average higher returns compared those with low margin betas. These result are important not only to understand asset prices, but also the unconventional polices implemented by the Fed during the great recession of 2007-2010. Although data on margin requirements for the S&P 500 futures are publicly available, it is in general very hard to obtain information on margins for other assets. Given that, we also propose a nonparametric model for estimating margins as a function of the asset's value at risk. This is theoretically justifiable and has good empirical results

Optimizing quantum-enhanced Bayesian multiparameter estimation in noisy apparata

Achieving quantum-enhanced performances when measuring unknown quantities requires developing suitable methodologies for practical scenarios, that include noise and the availability of a limited amount of resources. Here, we report on the optimization of quantum-enhanced Bayesian multiparameter estimation in a scenario where a subset of the parameters describes unavoidable noise processes in an experimental photonic sensor. We explore how the optimization of the estimation changes depending on which parameters are either of interest or are treated as nuisance ones. Our results show that optimizing the multiparameter approach in noisy apparata represents a significant tool to fully exploit the potential of practical sensors operating beyond the standard quantum limit for broad resources range

Non-asymptotic Heisenberg scaling: experimental metrology for a wide resources range

Adopting quantum resources for parameter estimation discloses the possibility to realize quantum sensors operating at a sensitivity beyond the standard quantum limit. Such approach promises to reach the fundamental Heisenberg scaling as a function of the employed resources $N$ in the estimation process. Although previous experiments demonstrated precision scaling approaching Heisenberg-limited performances, reaching such regime for a wide range of $N$ remains hard to accomplish. Here, we show a method which suitably allocates the available resources reaching Heisenberg scaling without any prior information on the parameter. We demonstrate experimentally such an advantage in measuring a rotation angle. We quantitatively verify Heisenberg scaling for a considerable range of $N$ by using single-photon states with high-order orbital angular momentum, achieving an error reduction greater than $10$ dB below the standard quantum limit. Such results can be applied to different scenarios, opening the way to the optimization of resources in quantum sensing

Optimizing quantum-enhanced Bayesian multiparameter estimation of phase and noise in practical sensors

Achieving quantum-enhanced performances when measuring unknown quantities requires developing suitable methodologies for practical scenarios, which include noise and the availability of a limited amount of resources. Here, we report on the optimization of substandard quantum limit Bayesian multiparameter estimation in a scenario where a subset of the parameters describes unavoidable noise processes in an experimental photonic sensor. We explore how the optimization of the estimation changes depending on which parameters are either of interest or are treated as nuisance ones. Our results show that optimizing the multiparameter approach in noisy apparata represents a significant tool to fully exploit the potential of practical sensors operating beyond the standard quantum limit for broad resources range

Securities Lending and Short Selling

Purpose – The aim of this study is to offer the current view on the subject, placing emphasis on studies that use Brazilian data and that could motivate new research. Design/methodology/approach –A bibliographic review of related studies and a secondary database. Findings – The contribution is to introduce this topic for the academic community in Brazil. We also present the main descriptive information for this market and its economic and policy implications. Originality/value – We contribute to the literature by summarizing the main works in the field, focusing on the Brazilian market, which has very detailed data and great potential for further studies

Transport Through Andreev Bound States in a Graphene Quantum Dot

Andreev reflection-where an electron in a normal metal backscatters off a superconductor into a hole-forms the basis of low energy transport through superconducting junctions. Andreev reflection in confined regions gives rise to discrete Andreev bound states (ABS), which can carry a supercurrent and have recently been proposed as the basis of qubits [1-3]. Although signatures of Andreev reflection and bound states in conductance have been widely reported [4], it has been difficult to directly probe individual ABS. Here, we report transport measurements of sharp, gate-tunable ABS formed in a superconductor-quantum dot (QD)-normal system, which incorporates graphene. The QD exists in the graphene under the superconducting contact, due to a work-function mismatch [5, 6]. The ABS form when the discrete QD levels are proximity coupled to the superconducting contact. Due to the low density of states of graphene and the sensitivity of the QD levels to an applied gate voltage, the ABS spectra are narrow, can be tuned to zero energy via gate voltage, and show a striking pattern in transport measurements.Comment: 25 Pages, included SO